Milling-cutter.



.PATENTED MAR. 3, 1908.

I 14514 /N Vin W 0 ,a Z J 1 1 1 I llllll 11 v ii a R. BANNISTER.

MILLING CUTTER.

APPLICATION FILED DBO. 29,1906.

ROBERT BAN N ISTER, OF BIRMINGHAM, ENGLAND.

MILLING-CUTTER.

Specification of Letters Patent.

Patented March 3, 1908.

Application filed December 2&1906- Serial No. 349.993.

To all whom it may concern:

Be it known that 1, ROBERT BANNISTER, subject of Great Britain, residingat 5 Latimer street, Bath Row, in the city of Birmingham, England, haveinvented new and useful Improvements Relating to Milling-Cutters, ofwhich the following is a specification.

This invention relates to milling cutters as employed for the cutting orshaping of metals and other materials and of the type in which a numberof separate tools are secured around the periphery of a body part orholder.

The invention has for its object the eco nomical construction of millingcutters as aforesaid with simple and effective means whereby theseparate tools can be readily attached and detached as required.

The invention dependent cutting tools of cylindrical form insertedwithin correspondingly shaped apertures disposed in any suitablearrangement around the periphery of a body part or holder, and-acylindrical cotter pin for each tool fitting within an aperture in theholder formed parallel with the cutting tool aperture, the adj acentportions of the tools and cotter pins being formed with oppositelyinclined flat faces whereby a wedging action can be set up betweenthem,- and also the provision of means as hereinafter described wherebythe aforesaid cotters can be individually withdrawn for the removal ofthe cutting tools as required.

Referring to the accompanying sheet of explanatory drawings :Figure 1 isa longi tudinal section and Fig. 2 a transverse section of a millingcutter constructed in accordance with this invention. Figs. 3 and 4 arerespectively longitudinal and transverse sections, to a larger scalethan Figs. 1. and 2, of the cotter ejecting device.

The same reference letters in the different views indicate the sameparts.

In the construction of a milling cutter as illustrated, the body part orholder a, which is provided with a central bore for the reception of amandrel in the ordinary manner, is drilled around its periphery with anumber of radial cylindrical apertures, and into the said aperturescutting tools I) madefrom steel of corresponding cross section areinserted. The holder is preferably made, as is customary, from castiron, mild steel, or other suitable metal that is less costly than thatfrom which the tools are made. The

comprises a number of in-.

shown in conjunction with the punch e.

tool apertures in the holder are sufficiently deep to provide anadequate support for the inserted cutting tools, but completepenetration to the bore of the holder is avoided whenever practicable inorder that by the material at the base of such apertures an abutment maybe provided for the inner ends of the tools.

Adjacent to each of the tool apertures a cylindrical cotter aperture isformed parallel therewith for the reception of a correspondingly shapedsteel cotter c. The cotter apertures extend from bore of the holder aand are drilled sufiiciently' close to the tool apertures as tointersect the latter and thus enable the cotters a to abut laterallyagainst the tools 6. Along adjacent portions both the tools and the cotters are formed (by grinding, filing or other ordinary operations) withhat longitudinal surfaces which are oppositely inclined in the directionof their length so that a wedging action can be set up between them.After the tools have been inserted in their apertures the cotters areplaced in position and driven sufficiently to provide for the requiredsecurity of the tools.

Usually it is advisable to have as little as possible of the tools I)projecting beyond the holder a in order to obtain sufiicient rigidity ofthe tools; the cotters must therefore necessarily be driven so far intothe block a as to render it inconvenient to withdraw the same by anappliance acting on their outer ends.

For the withdrawal of the cotters, an ejecting tool is consequentlyinserted within the bore of the body part or holder and arranged tooperate individually on the inner ends of each of the cotters to bewithdrawn. The said tool comprises essentially a punch e adapted to beplaced in line with the cotters and a plunger d arranged coaxially withthe milling cutter for operating the punch. The adjacent extremities ofthe punch and plunger are inclined at about forty-five degrees or areotherwise so adapted that when a blow is given to the plunger (1, suchas by means of a hand hammer, a movement at right angles is given to thepunch. Both the punch and plunger are carried in a suitable holder whichcan be, inserted bodily in the bore of the milling cutter. A spring 9 isarranged in conjunction with either the punch or plunger to restore bothto their initial position after each blow. In the drawings the spring 9is A on the body f serves for positioning nipple f the ejector, the saidnipple being inserted 1n described can be readily produced at smallcost, and the cutters very conveniently renewed when required. In theevent of breakage of one of the tools this can be replaced withoutinterfering with the others, as the cotters, while providing amplesecurity when in use, can be easily withdrawn. By suitably arranging thetool apertures any required disposition of the tools can be obtained,and by varying the relation of the tool and cotter apertures the cotterscan be situated either at the front or rear of the tools. In the aplication of the invention to a face cutter t e tools are also securedas aforesaid, the cotter a ertures being then made to pass from one si eor face to the other so that the cotters can be convenientlywithdrawn.

Having thus described my invention what I claim and desire to secure byLetters Patent is In milling cutters, the combination consisting of aholder, cylindrical tool apertures around the said holder, cylindricalcotter apertures formed exactly parallel with and intersecting the saidtool apertures, cylindrical tools fitted within the tool apertures andeach provided with a flat surface inclined to the aXis of the tool, andcylindrical cotters fitted into the cotter apertures and each formedwith a flat surface oppositely inclined to those on the tools,substantially as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ROBERT BANNISTER.

WVitnesses:

JOHN MORGAN, HARRY DAVIS.

